Population Health Sciences, University of Wisconsin, Madison, WI, USA.
Sleep. 2011 Jun 1;34(6):745-50. doi: 10.5665/SLEEP.1040.
To compare the breathing instability and upper airway collapsibility between patients with pure OSA (i.e. 100% of apneas are obstructive) and patients with predominant OSA (i.e., coexisting obstructive and central apneas).
A cross-sectional study with data scored by a fellow being blinded to the subjects' classification. The results were compared between the 2 groups with unpaired student t-test.
Standard polysomnography technique was used to document sleep-wake state. Ventilator in pressure support mode was used to introduce hypocapnic apnea during CO(2) reserve measurement. CPAP with both positive and negative pressures was used to produce obstructive apnea during upper airway collapsibility measurement.
21 patients with OSA: 12 with coexisting central/mixed apneas and hypopneas (28% ± 6% of total), and 9 had pure OSA.
The upper airway collapsibility was measured by assessing the critical closing pressure (Pcrit). Breathing stability was assessed by measuring CO(2) reserve (i.e., ΔPCO(2) [eupnea-apnea threshold]) during NREM sleep.
There was no difference in Pcrit between the 2 groups (pure OSA vs. predominant OSA: 2.0 ± 0.4 vs. 2.7 ± 0.4 cm H(2)O, P = 0.27); but the CO(2) reserve was significantly smaller in predominant OSA group (1.6 ± 0.7 mm Hg) than the pure OSA group (3.8 ± 0.6 mm Hg) (P = 0.02).
The present data indicate that breathing stability rather than upper airway collapsibility distinguishes OSA patients with a combination of obstructive and central events from those with pure OSA.
比较单纯阻塞性睡眠呼吸暂停（即 100%的呼吸暂停为阻塞性）和以阻塞性和中枢性呼吸暂停并存为主的睡眠呼吸暂停（即主要阻塞性）患者的呼吸不稳定和上气道塌陷程度。
这是一项横断面研究，评分由一位对研究对象分类不知情的同事进行。通过配对学生 t 检验比较两组之间的结果。
使用标准多导睡眠图技术记录睡眠-觉醒状态。在二氧化碳储备测量过程中，使用压力支持模式的呼吸机引入低碳酸血症性呼吸暂停。在评估上气道塌陷程度时，使用正、负气压的 CPAP 产生阻塞性呼吸暂停。
21 例 OSA 患者：12 例存在中枢/混合性呼吸暂停和低通气（占总例数的 28%±6%），9 例存在单纯 OSA。
上气道塌陷程度通过评估临界关闭压力（Pcrit）进行测量。呼吸稳定性通过在非快速眼动睡眠期间测量二氧化碳储备（即 NREM 睡眠时的 PCO2 变化[呼吸暂停-觉醒阈值]）进行评估。
两组间 Pcrit 无差异（单纯 OSA 与主要 OSA：2.0±0.4 对 2.7±0.4 cm H2O，P=0.27）；但主要 OSA 组的 CO2 储备（1.6±0.7 mmHg）显著小于单纯 OSA 组（3.8±0.6 mmHg）（P=0.02）。
目前的数据表明，呼吸稳定性而非上气道塌陷程度可区分以阻塞性和中枢性事件并存为主的 OSA 患者和单纯 OSA 患者。
